Wafer level hermetic sealing method

• US 6,969,639 B2
• Filed: 10/31/2001
• Issued: 11/29/2005
• Est. Priority Date: 02/03/2001
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Shin, Hyung-jae, Kim, Woon-bae, Cho, Chang-ho
• Primary Examiner(s): Coleman, W. David
• Assistant Examiner(s): Nguyen, Khiem D.
• Application Number:
  US09/984,734
• Publication Number:
  US 20020113296A1
• Time in Patent Office: 1,490 Days
• Field of Search: 438/118, 438/125, 438/110, 438/113, 438/108, 438/119, 438/458, 257/704, 257/783, 257/659
• US Class Current: 438/118
• CPC Class Codes: B81B 7/0077 Other packages not provided for in groups B81B7/0035 - B81B7/0074
• CPC Class Codes: B81C 1/00269 Bonding of solid lids or wafers to the substrate
• CPC Class Codes: B81C 1/00357 involving bonding one or several substrates on a non-temporary support, e.g. another substrate
• CPC Class Codes: B81C 2201/019 Bonding or gluing multiple substrate layers
• CPC Class Codes: H01L 21/50 Assembly of semiconductor devices using processes or apparatus not provided for in a single one of the subgroups H01L21/06 - H01L21/326, e.g. sealing of a cap to a base of a container
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/85399 Material
• CPC Class Codes: H01L 23/10 characterised by the material or arrangement of seals between parts, e.g. between cap and base of the container or between leads and walls of the container
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/01322 Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/10253 Silicon [Si]
• CPC Class Codes: H01L 2924/12041 LED
• CPC Class Codes: H01L 2924/16235 Connecting to a semiconductor or solid-state bodies, i.e. cap-to-chip
• CPC Class Codes: H01L 2924/207 Diameter ranges

Abstract

A device that is hermetically sealed at a wafer level or a method of hermetically sealing a device, which is sensitive to high temperatures or affected by heating cycles. Semiconductor devices are formed on a wafer. A lid wafer is formed. Adhesives are formed in a predetermined position over the wafer and/or the lid wafer. The wafer and the lid wafer are sealed by the adhesives at the wafer level. The sealing may be performed at a low temperature using a solder to protect the devices sensitive to heat. The sealed devices are diced into individual chips. In the wafer level hermetic sealing method, a sawing operation is performed after the devices are sealed. Therefore, the overall processing time is reduced, devices are protected from the effects of moisture or particles, and devices having a moving structure, such as MEMS devices, are more easily handled.

Claims

1. A wafer level hermetic sealing method comprising:

forming semiconductor devices on a device side of a wafer;

forming a lid wafer having a front side and a through hole at a predetermined position, with the through hole being formed before the wafer and the lid wafer are sealed;

forming adhesives in predetermined positions over the device side of the wafer or the front side of the lid wafer;

sealing the device side of the wafer and the front side of the lid wafer with the adhesives; and

dicing the sealed wafer-level devices into individual chips,

wherein the adhesives are formed of a material having a fusion point of 100˜

300°

C.

2. The wafer level hermetic sealing method of claim 1, wherein the adhesives are formed of one selected from the group consisting of In, Sn, Ag, Pb, Zn, Au, Bi, Sb, Cd, Ga and Cu, or an alloy of two or more of these metals.

3. The wafer level hermetic sealing method of claim 2, wherein the forming of the adhesives comprises depositing or sputtering the adhesives.

4. The wafer level hermetic sealing method of claim 2, wherein the forming of the adhesives comprises forming adhesive promoters over the device side of the wafer and/or the front side of the lid wafer to promote adhesion of the adhesives.

5. The wafer level hermetic sealing method of claim 4, wherein the forming of the adhesive promoters comprises disposing the adhesives and the adhesive promoters to align the wafer with the lid wafer.

6. The wafer level hermetic sealing method of claim 4, wherein the adhesive promoters are formed of metal or polymer.

7. The wafer level hermetic sealing method of claim 2, further comprising forming electrical connectors on the wafer to transceive an electrical signal.

8. The wafer level hermetic sealing method of claim 7, wherein the forming of the lid wafer further comprises forming the through hole in a predetermined position so that the electrical connectors are electrically connectable to the outside via an interconnection line passing through the through hole.

9. The wafer level hermetic sealing method of claim 2, wherein the adhesives have a preformed shape.

10. The wafer level hermetic sealing method of claim 2, wherein the lid wafer is a transparent material to exchange an optical signal.

11. The wafer level hermetic sealing method of claim 1, wherein the adhesives are formed by deposition or sputtering.

12. The wafer level hermetic sealing method of claim 1, wherein the forming of the adhesives comprises forming adhesive promoters over the device side of the wafer and/or the front side of the lid wafer to promote adhesion of the adhesives.

13. The wafer level hermetic sealing method of claim 12, wherein the forming of the adhesive promoters comprises disposing the adhesives and the adhesive promoters to align the wafer with the lid wafer.

14. The wafer level hermetic sealing method of claim 12, wherein the adhesive promoters are formed of metal or polymer.

15. The wafer level hermetic sealing method of claim 1, further comprising forming electrical connectors on the wafer to transceive an electrical signal.

16. The wafer level hermetic sealing method of claim 15, wherein the forming of the lid wafer further comprises forming the through hole in a predetermined position so that the electrical connectors are electrically connectable to the outside via an interconnection line passing through the through hole.

17. The wafer level hermetic sealing method of claim 1, wherein the adhesives have a preformed shape.

18. The wafer level hermetic sealing method of claim 1, wherein the lid wafer is a transparent material to exchange an optical signal.

19. The wafer level hermetic sealing method of claim 1, wherein the adhesives are formed of solder, metal, or an organic sealant.

20. The wafer level hermetic sealing method of claim 1, wherein the semiconductor devices are microelectromechanical systems (MEMS) devices.

21. The wafer level hermetic sealing method of claim 1, wherein the semiconductor devices are charge coupled devices.

22. The wafer level hermetic sealing method of claim 1, wherein the semiconductor devices are sensors.

23. A method comprising:

forming semiconductor devices on a wafer;

adhering a lid wafer, having a through hole at a predetermined position and formed before the wafer and the lid wafer are sealed at a wafer level, to the wafer;

sealing the wafer and the lid wafer at the wafer level; and

separating the sealed semiconductor devices into individual chips,

wherein the adhering comprises adhering the wafer and the lid wafer using adhesives comprising a material having a fusion point of 100˜

300°

C.

24. The method of claim 23, wherein:

the adhering further comprises;

forming the adhesives at predetermined positions on at least one of the lid wafer and the wafer, and

adhering the wafer and the lid wafer with the adhesives so that enclosures with cavities are formed by the lid wafer, the wafer and the adhesives, wherein the semiconductor devices are within the cavities; and

the separating comprises separating the sealed semiconductor devices at positions between the enclosures.

25. The method of claim 23, wherein the semiconductor devices are micro-electromechanical systems (MEMS) devices.

26. The method of claim 23, further comprising attaching the individual chips to a package after the sealing of the wafer and the lid wafer.

27. A method comprising:

forming semiconductor devices on a wafer;

adhering a lid wafer, having a through hole at a predetermined position, to the wafer using adhesives made of a material having a fusion point of 100˜

300°

C. with the through hole being formed before the lid wafer is adhered to the wafer;

sealing the wafer and the lid wafer at a wafer level; and

separating the sealed semiconductor devices into individual chips.

28. The method of claim 27, wherein the material is solder.